As long as the temperature of the milk and watermelon is appropriate and there is no deterioration, milk and watermelon together generally will not have diarrhea. Milk and watermelon are common foods in daily life, milk is rich in protein, calcium and other nutrients, watermelon is rich in vitamins, minerals and other nutrients, as long as the milk and watermelon to keep eating at the right temperature, i.e., the temperature should not be too low and there is no spoilage, contamination and other situations can be eaten together, will not diarrhea. Although milk and watermelon can be eaten together, it is important to eat in moderation to avoid indigestion and other discomfort. If you experience discomfort after eating milk and watermelon, it is recommended that you go to the hospital.